| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 563 | 225 | 6 | 3% |
| Alpine | - | - | - | - |
| Amador | 2 | - | - | - |
| Butte | 62 | 13 | - | - |
| Calaveras | 8 | - | - | - |
| Colusa | 13 | 4 | 1 | 25% |
| Contra Costa | 515 | 53 | 3 | 6% |
| Del Norte | - | - | - | - |
| El Dorado | 73 | 17 | - | - |
| Fresno | 160 | 17 | 11 | 65% |
| Glenn | 7 | - | - | - |
| Humboldt | 17 | - | - | - |
| Imperial | 3 | - | - | - |
| Inyo | 1 | - | - | - |
| Kern | 45 | 4 | 1 | 25% |
| Kings | 17 | - | - | - |
| Lake | 20 | 10 | 1 | 10% |
| Lassen | 1 | - | - | - |
| Los Angeles | 781 | 98 | 5 | 5% |
| Madera | 16 | 3 | - | - |
| Marin | 88 | 4 | - | - |
| Mariposa | 1 | - | - | - |
| Mendocino | 15 | - | - | - |
| Merced | 48 | 4 | 1 | 25% |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 38 | 5 | - | - |
| Napa | 30 | 6 | - | - |
| Nevada | 32 | 4 | - | - |
| Orange | 443 | 157 | 4 | 3% |
| Placer | 228 | 83 | 8 | 10% |
| Plumas | 3 | - | - | - |
| Riverside | 177 | 48 | - | - |
| Sacramento | 804 | 298 | 27 | 9% |
| San Benito | 4 | 1 | - | - |
| San Bernardino | 138 | 31 | - | - |
| San Diego | 467 | 175 | 33 | 19% |
| San Francisco | 105 | 13 | - | - |
| San Joaquin | 215 | 49 | 7 | 14% |
| San Luis Obispo | 63 | 11 | - | - |
| San Mateo | 578 | 180 | - | - |
| Santa Barbara | 51 | 18 | - | - |
| Santa Clara | 805 | 172 | 26 | 15% |
| Santa Cruz | 108 | 33 | - | - |
| Shasta | 17 | 6 | - | - |
| Sierra | 1 | - | - | - |
| Siskiyou | 3 | - | - | - |
| Solano | 150 | 33 | 3 | 9% |
| Sonoma | 157 | 16 | 1 | 6% |
| Stanislaus | 161 | 13 | 1 | 8% |
| Sutter | 27 | 8 | 1 | 13% |
| Tehama | 14 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 73 | 20 | 8 | 40% |
| Tuolumne | 5 | - | - | - |
| Ventura | 132 | 22 | 1 | 5% |
| Yolo | 222 | 47 | 5 | 11% |
| Yuba | 29 | 7 | - | - |
| State Totals | 7737 | 1908 | 154 | 8% |
* Birds in a die-off are not included in reported totals because the deaths are not related to WNV. A die-off is defined as a group of 10 or more same species dead birds unless the species is American Crow.
Source: Vector-Borne Disease Section, California Department of Public Health